1. Field of the Invention
The present invention relates to a catalyst used in a reaction for manufacturing a hydrogen gas by reforming a hydrogen-containing gas such as methanol, etc. More particularly, a catalyst for a methanol gas reforming reaction for generating the hydrogen-containing gas that is suitable for a fuel gas supplied to a fuel cell used in a power source of a mobile body, etc.
2. Description of the Related Art
The fuel cell is a device that directly converts a chemical energy of a fuel into an electrical energy and can achieve high energy conversion efficiency. The major fuel employed in the fuel cell is hydrogen, but a fuel gas (reformed gas) containing hydrogen and carbon dioxide except the hydrogen can be employed in the fuel cell such as a polymer electrolyte fuel cell, a phosphoric acid fuel cell, a molten carbonate fuel cell, etc. For this reason, in the fuel cell system having these fuel cells, a reforming apparatus that reforms the fuel (hydrogen-containing fuel) to generate a reformed gas containing the hydrogen is provided.
In the reforming apparatus in the prior art, a reforming reaction for reforming a methanol gas by using a Steam to generate the hydrogen, i.e., a steam reforming reaction expressed by following Eq. (f1), is carried outCH3OH+H2O→CO2+3H2  (f1)
Since the steam reforming reaction (f1) is the endothermic reaction, heating is applied by providing a burner, a heater, or the like to the reforming apparatus and thus a heat quantity necessary for start and maintenance of the reforming reaction is supplied.
Also, as a reforming catalyst for promoting the above reforming reaction, the copper-zinc (Cu—Zn) based catalyst disclosed in Laid-Open Patent Publication Hei 5-261288 published in 1993 is used. This Cu—Zn based catalyst has high reaction selectivity in the steam reforming reaction, but a copper component serving as the reaction active species is copper oxide in its initial state, and therefore the reducing process must be performed at 250 to 300 ° C. prior to use. This reducing process may be conducted in the reforming apparatus, otherwise the reducing apparatus for performing the reducing process using the hydrogen may be attached separately.